Nickel-catalyzed organozinc-promoted carbocyclizations of electron-deficient alkenes with tethered unsaturation
Nickel-catalyzed organozinc-promoted carbocyclizations of electron-deficient alkenes with tethered unsaturation
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DOI：
10.1021/ja9702125
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发表时间：
1997-05
影响因子：
15
通讯作者：
J. Montgomery;E. Oblinger;A. V. Savchenko
中科院分区：
文献类型：
--
作者：
J. Montgomery;E. Oblinger;A. V. Savchenko
提出了在有机化合物存在下，镍催化拴链不饱和的缺电子烯烃环化反应的方法。在每个反应组分的结构中观察到相当大的灵活性。烯酮、丙二酸烷基烯、不饱和β-酮酯和硝基烯作为缺电子烯烃参与；炔烃、烯酮、1,3-二烯和醛作为栓系不饱和参与；各种sp2和sp3杂化有机物，包括那些具有β-氢的有机物，作为亲核组分参与了反应。底物结构、有机锌结构和配体结构都对产物的选择性起重要作用。特别具有合成意义的是有机会从普通炔制备E或Z三取代或四取代烯烃。对可能的机制进行了讨论。
A nickel-catalyzed method for cyclizations of electron-deficient alkenes with tethered unsaturation in the presence of organozincs was developed. Considerable flexibility in the structure of each reactive component was observed. Enones, alkylidene malonates, unsaturated β-ketoesters, and nitroalkenes participated as the electron-deficient alkene; alkynes, enones, 1,3-dienes, and aldehydes participated as the tethered unsaturation; and a variety of sp2 and sp3-hybridized organozincs, including those that possess β-hydrogens, participated as the nucleophilic component. Substrate structure, organozinc structure, and ligand structure all played a significant role in determining product selectivities. Of particular synthetic significance was the opportunity to prepare either E or Z tri- or tetrasubstituted alkenes from a common alkyne. A discussion of probable mechanisms is provided.